1. Field of the Invention
The present invention relates to a system, method, computer program product, and apparatus for automatically ensuring the consistency of Program and System Information Protocol (PSIP) tables and Program Specific Information (PSI) tables in a digital television stream.
2. Discussion of the Background
As digital television (DTV) evolves and becomes more popular, techniques for exploiting this new technology will evolve as well. The transport layer of an Advanced Television Systems Committee (ATSC) DTV signal is based on the Moving Pictures Expert Group (MPEG-2) standard. An ATSC DTV-compliant stream includes the MPEG-2 information, but also provides additional information.
MPEG-2 defines, among other things, a basic set of tables called Program Specific Information (PSI) tables that include tuning information that allows a receiver to “tune to” (or identify) the individual components of a program (e.g., video, audio, and data) within the digital television stream.
The ATSC standard A/65, the entire contents of which being incorporated herein by reference, specifies the addition of tables to meet various specific requirements that, for example, support United States DTV standards. These tables are Program and Specific Information Protocol (PSIP) tables and provide, for example, tuning information, branding information, and program guide information. The tuning information provided in the PSIP tables is largely duplicative of the information contained in the MPEG PSI tables, however, some additional features are added as well. The branding information provided in the PSIP tables provides a two-part channel number that links each digital channel to the analog channel (or main channel) of the station (e.g., channel 4). The program guide information provided in the PSIP tables provides electronic program guide (EPG) information.
Due to the redundancy of the tuning information in the PSI tables and the PSIP tables, manufacturers of DTV-compliant devices have been faced with a decision as to whether to access tuning information from the PSI tables or the PSIP tables, since both are transmitted in the ATSC stream. Some receivers are configured to use the tuning information from the PSI tables, and others are configured to use the tuning information from the PSIP tables.